Clinical anatomy of the anterolateral vein of lower lumbar spine and its significance with retroperitoneal endoscopic surgery

objective: to explore the anatomic characteristics of veins situated at the lower lumbar spine and provide anatomic data for laparoscopic lumbar surgery. Methods: 15 formaldehyde-preserved cadavers were studied with special attention to the variety and surrounding structure of ascending lumbar vein (ALV) and iliolumbar veins(ILV) , and their relationship with lumbar plexus. Results: ALV and ILV can be found in every sample, which included four variant forms concerning with separate entry and common entry. For 18 cases, the ascending vein and iliolumbar vein separately drained into common iliac vein, and for 12 cases a common trunk entered into the common iliac vein. When dragging common iliac vein medially for the exposure of the disc space,both the ascending lumbar and the iliolumbar veins were always at the risk of avulsion. At the process of exposing vessels, the injury of obturator nerve and lumbosacral trunk of the lumbar plexus may be occurred. Conclusions: Awareness of those anatomic variation should assist a surgeon to perform a careful ligation of these veins before medially retracting of the common iliac vein and prevent the possibility of hemorrhage. Our findings emphasize the necessity for proper dissection of the ALV and ILV before ligating them during the exposure of the lower lumbar spine.